Thermal drill and drilling process



2 Sheets-Shed 1` ATTORNEYS July 28, 1959 M. A. RYANv 'i THERMAL DRILL AND -DRILLING PRocEss Filed 'June 1e.v 1955 M. A. RYAN 2 Sheets-Sheet 2 llv'l/ENTOR.`

M. A. RYAN BY Zi z ATTORNEYS July 28, 1959 THERMAL DRILL AND DRILLING PROCESS Filed June 16, l1955 2,896,914 THERMAL mum. AND DRILLING PROCESS Martin A. Ryan, Bartlesville, Okla., assignor to Phillips Y Petroleum Company, a corporation of Delaware Application June 16, 1955, Serial No. 515,940

20 Claims. (Cl. Z55-1.8)

' This invention relates to an improved process and drill for thermal drilling in an earth formation, particularly rock and rock-like formations. A specific aspect of the invention pertains to an improved nozzle for a thermal drill.

' The use of thermal drills in piercing earth formations, particularly rock and rock-like minerals, is conventional. In one type of drill the flame is produced by burning a post-mixed combustible mixture of oxygen and fuel wherein all ofthe burning takes place outside of the blowpipe. Another type of thermal drill, such as that disclosed in the U.S. Patent 2,675,993 of George H. Smith et al., produces a ame in an internal combustion chamber into which lthe combustible mixture is injected before burning. Both of these types of thermal drills have limitations, particularly as to the rate of piercing or drilling a rock formation, because of the limited heat release possible with the type of mixing which they utilize. I have devised a thermal drill nozzle and burner which provides an improved method or type of mixing and simultaneously burning fuel and oxygen in a nozzle ICC resulting from or eifected by the shear'action and turbulence at the shear interface between the two masses of as.

g more complete understanding'of the invention may be had by reference to the accompanying schematic draw* ing of 'which Figure l is a longitudinal partial cross section of one embodiment of the thermal drill of the invention; Figure 2 is a plan view ofthe outlet end of the drill nozzle of Figure l; Figure 3 is a longitudinal cross section of another embodiment ofthe improved drill nozzle of the invention showing a dilferent means provide a cooling chamber 18. Burner tube 16 is which effects vastly higher heat release than the burners of presently known thermal drills.

The principal object of the invention is to provide an improved thermal drill and process for drilling or piercing bore holes in an earth formation. Another object is to provide an improved thermal drill and drilling method which permit drilling at increased rates. Another object is to provide a thermal drill capable of increased heat release as compared with presently known thermal drills. A further object of the invention is to provide an improved drill and method of drilling which are particularly effective in drilling bore holes in iron-bearing rock, such as taconite. It is also an object of the invention to provide an improved drill nozzle for use in a thermal drill and in a drilling process. Other objects of the invention Will become apparent from a consideration of the accompanying disclosure.

The invention comprises a process for thermal drilling wherein a fluid fuel is burned in admixture with oxygen with which it mixes by shearing turbulence occurring at the' interface between an annular mass of one of the fluids moving through a combustion zone of circular transverse section in a burner nozzle and an axial mass of threaded into housing 14 at 20. An axial gas distributor 22 is threaded into adapter 24' (by threads not shown) and cooperates with annular member 26 to form annular conduit or fluid inlet 28 at the inlet end of flame-.tube 16. An annular fluid distributor 30 is formed by members 22, 24, and 26. Fluid inlet conduit 32 is connected with annulus 30 by means of channel or conduit 34. Axial gas distributor 22 is provided with a core member 36 and 4with a series of swirl `vanes 38 disposed in the annulus 40 surrounding core 36. Annulus 40 is connected directly with fluid inlet conduit 42.

Annular cooling chamber 18 is supplied with cooling fluid, such as water,l from conduit 13 by conduit means including conduits 44, 45, and 46 and annular conduits 47 and 48. A plurality of conduits 44, 45, and 46 may bev formed in the structure. Cooling fluid is ejected from the nozzle via ports 50 which are upwardly directed so as to eject the Huid upwardly in the annulus surrounding the drill nozzle and enclosedby the borehole thereby adding to the lifting effect of the eluent gas. Radial drill teeth 52 having forward cutting edges 53 are rigidly attached to or formed integrally with-nozzle housing 14 and preferably extend around the ynose of the nozzle to flame outlet 56. I

Swirl vanes 38 are several in number,1such as lshown in Figure 2, and are positioned in a helical pattern around 'core 36 in annulus 40 so as to impart a swirling helical movement of the mass of fluid introduced through conduit 42 to the inlet end of ame. tube 16. These swirl vanes are symmetrically positioned at an angle in the 4range of 30 to 60 and preferably atabout 45 in order to provide suitable swirl to the axial core of gas intro the other fluid swirling helically inside and adjacent the annular mass, directing the efuent iiame and combustion gas against the formation or rock to be pierced or drilled so as to separate material therefrom by spalling and/or melting, and removing the separated material from the resulting bore hole; and a thermal drill which effects such a process. It Ihas been found that this shearing turbulence method of burning effects a heat release of about 5() million. B.t.u. per cubic foot of mixing and burning space as compared with a heat release of about 3 million B.t.u. per cubic foot for a conventional burner. The drilling effectiveness of the improved burner and process is roughly proportional to the heat release. The improvement in heatrelease isl believed to be due to more eftcient mixing.,andburningofpxygen and --fuel J.f.

swirling core of gas produced by owing gas :between swirl vanes 38.

Fluid fuel distributing member 11 comprises an annular body member or sleeve 60 in whichis journaled a core member 61 designed to rotate therein and provided with suitablel packing materiall 62. Core v61 is retained in annular ybody member 60 by a llangek 6,4 on the lower end of the core and by nut 65 threaded on its upper end and bearing on retainer plate 66. Axial conduit 68 in core 61 connects with inlet conduit 42of burner nozzle 12 and connectsy on the upper endwith nipple 70 which is attached to a swivel 71 which, in turn, connects with a lsi'ipply coni duit72. V-Annular body member 60 is provided with aus nular duid distributing ,conduits 74 and 75 which are C011- nected to inlet nipples 76 and 77, respectively. Conduit 79 connects at its upper end with annular distributing conduit 75 and at vits lower end with iluid'inlet conduit 32. connecting with the burner nozzle. Conduit 80 in core 61 connects at its upper end with annular distributing conduit 74 and at its lower end with conduit 13 which supplies coolant to the drill nozzle.

In operation nozzle 12 is directed against the locus of the bore hole and the burner is ignited by any suitable means, such as a spark plug, not shown, or by means of a match or lighting torch before insertion in the bore hole. Oxygen or air iS introduced, preferably throughfsllPPly conduit 72, axially of the drill and burner, entering the flame or burner tube 16 axially thereof through conduit 42 and annulus 40 around swirl vanes 38 which impart a swirling movement tothe incoming air thereby establishing an axially and helically moving mass of air or oxygen through the inlet end section of the flame tube. Simultaneoutsly, fuel is introduced in an annular mass moving through the inlet end of the flame tube from annulus 28 by means of fuel inlet 77 and the connecting conduits including conduit 32. The rates of flow of fuel and oxygen are controlled so as to provide at least a stoichiometric excess of oxygen. The essential feature of the invention is the maintenance of a swirling, helically moving core of oxygen or fuel in the inlet end section of the burner tube and an annular mass of the other component of the combustible combination surrounding the helically moving core so that exceptionally ecient mixing and burning takes place at the shear interface of the two masses of uid. While it is preferred to introduce the oxidant (free oxygen, air, or oxygen-enriched air) axially of the flame tube, it is also feasible to introduce the fuel to this section of the burner and the oxidant to the annulus surrounding the mass of core gas, with satisfactory results. The more suitable fuels are liquid hydrocarbons such as L.P.G., kerosene, gasoline, crude oil, fuel oil, etc. Butane, propane, and mixtures thereof are preferred to other fuels. The fuel may be introduced in vapor form to the drill head but it is preferred to vaporize the liquid fuel in the burner just before or as the same enters the ame tube by pressure drop and heat from the burner. In this manner the fuel enters the ame tube in vapor form and forms a vaporous annulus in the form of a sheath around the axial core of helically swirling oxidant.

Under some operating conditions when the melting exceeds the spalling ahead of drill nozzle 12 and the rate of slag formation is high, it may be desirable to rotate the drill nozzle so that radial teeth 52 extending longitudinally and across the end of the nozzle body so as to break up the slag and permit the removal of the resulting small particles in the gas stream emanating from the bore hole. When rotation is desired the same may be effected by conventional means such as that illustrated in the aforesaid Smith et al. patent, particularly Figure thereof.

The preferred cooling fluid is water, but other fluids, such as steam, inert gas, air, or mixtures thereof, may be utilized with satisfactory results. Water is highly efficient in cooling and is particularly desirable in view of the conversion of the water to steam with concomitant vast expansion thereof and resulting assistance of the expanded coolant in blowing or ejecting separated particles of the earth formation or rock out of the bore hole. The coolant also assists in cooling the drill and drill stem.

Referring to Figures 3, 4, and 5, the nozzle of this embodiment of the invention is similar to that of Figures 1 and 2 in that it comprises basically a nozzle or burner housing 14 surrounding in spaced-apart relation a flame or burner tube l'thereby providing a cooling chamber 18;v This nozzle also has means for introducing and maintaining a helically swirling core of uid in the feed end of the burner and means for introducing and maintaining an annularpmass of gas surrounding the axial core. 1.11111@ embodiment shown in Figure 3, the gas introduced from conduit 42 is passed outwardly to annulus 82 via conduits 83. From annulus 82 fluid passes inwardly through tangential conduits 84 to cylindrical chamber 85 leading into the inlet end of llame tube 16 and contiguous therewith. As shown more clearly in Figures 4 and 5, the

structure just described gives the fluid a first swirl in passing from axial inlet conduit 42 to annulus 32r through swirl tubes or conduits 83. As the fluid swirls in annulus 82 it passes through tangential tubes or conduits -84 'leading into cylindrical chamber 85 which effectively swirls the gas being introduced axially of the ame tube in a helical pattern around the axis thereof as it progresses through the flame tube and effectively mixes and burns the surrounding sheath or annular mass of fuel at the interface between the two masses. Additional fluid (preferably oxygen) passes from annulus 82 through conduit 87 into annular chamber 88 from which it passes into the ilame tube downstream of the inlet end via ports 89. In this manner the nozzle provides secondary oxidant for the fuel remaining unburned in the flame tube or combustion chamber as it reaches the vicinity of ports 89.

As in the nozzle of Figure l, fuel is the preferred uid introduced through conduit 32 to the inlet end of the nozzle. The fuel is passed from conduit 32 via conduit 90 to distributing annulus 30 from which it passes via an nular inlet 2S into the inlet end of the flame tube and is directed downwardly in an annular mass adjacent the wall of the tube as in the nozzle of Figure l.

In order to impart exceptionally high velocity to the effluent gas and flame, burner tube 16 is provided with venturi orifice or rocket motor exhaust nozzle 92, also known as a De Laval nozzle. The preferred included angle in this flared construction is 25 degrees since this irnparts the greatest velocity to the effluent gas under average conditions; however, satisfactory performance is pro.- vided when the angle of this exhaust nozzle is in the range of 15 to 35 degrees. n

Coolant is introduced into cooling chamber 13. from conduit 80 via connecting conduit 81. Chamber 18 sur.- rounds venturi 92 which is subjected to temperature conditions and is most in need of cooling. Additional cooling space around secondary air chamber 88 may be provided, if desired, but is not essential. The drill nozzle or burner and, particularly, the llame tube, is constructed of a high temperature alloy suitable for use in jet motor nozzles in `order to withstand the high temperatures developed 'by 'the highly efficient method of mixing and burning provided by kthe nozzle of the invention.

Various modifications of the two nozzles illustrated in the drawing and described herein will occur to anyone skilled in the art. To illustrate, the jet nozzle type ilame type of Figure 3 may be utilized in the drill nozzle of Figure l and, vice versa, the flame tube of Figure 1 may be utilized in the drill nozzle of Figure 3. It is also feasible to construct and operate the drill ofl Figure 3 without secondary oxidant ports 89. As pointed out above, it is `feasible to introduce the fuel axially and the oxidant peripherally of the flame rtube, although results are more satisfactory with axial introduction of the oxidant and peripheral introduction of the fuel. It is also feasible to operate the drill without radial drill teeth 52 and Without rotation of the drill nozzle in view of the fact that the thermal drill of the invention will pierce or drill a bore hole in a rock formation by simply spalling and/or melting the rock in the path of the drill and blowing the separated material out of thek bore hole without any cutting action of the teeth on the body of the nozzle when operating under most satisfactory conditions.

Certaing modications of the invention will become apparent to those skilled in the art and the illustrative I claim:

1. A thermal drill comprising in combination a body member having fuel and oxygen inlets; a pair of conduits connecting with said inlets and extending from said member; a burner nozzle connected with the ends of said conduits remote from said member; a cylindrical internal combustion chamber of greater length than diameter and disposed axially in said nozzle having an outlet in the end thereof remote `from said conduits; first conduit means in said nozzle connected with the inlet end of said combustion chamber and with one of said pair of conduits, said rst conduit means being directed and disposed so as to introduce and pass fluid helically around the axis of said chamber; and second conduit means connected with the other of said pair of conduits and with rthe inlet end of said combustion chamber radially outside of said rst conduit means, said second conduit means being directed and disposed so as to introduce and pass fluid along and adjacent the wall of said chamber parallel with its axis.

2. The drill of claim l including an inlet in said body member for a cooling fluid; an enclosed cooling chamber around said combustion chamber having at least one outlet adjacent the outlet end of said combustion chamber; third conduit means connected with last said inlet and with said cooling chamber remote from the outlet therein.

3. The drill of claim 2 including radical teeth on the outside of said nozzle extending longitudinally thereof.

4. The drill of claim 3 wherein said teeth extend over the outlet end of said nozzle to the outlet therein.

5. The drill of claim 1 wherein said body member comprises a sleeve surrounding a rotatable core journaled therein, said pair of conduits connecting said core with said nozzle and with said inlets during rotation of said core.

6. The drill of claim 5 including an attaching conduit surrounding said pair of conduits and rigidly attached to said core and to said nozzle at opposite ends; a conduit for coolant leading through said core to the interior of said attaching conduit; and a cooling chamber in said nozzle surrounding said combustion chamber having at least one outlet adjacent the outlet end of said nozzle, said cooling chamber being connected by conduit means leading from the interior of said attaching conduit so as to provide a ow path for coolant through said drill and out said at least one outlet.

7. The drill of claim l wherein said first conduit means comprises a rst yannulus coaxial with and opening into said chamber, and spaced-apart baies in said first annulus arranged to direct fluid around the core of said iirst annulus as it passes therethrough to said chamber, said first annulus being connected with said one of said pair of conduits; and wherein said second conduit means comprises a second annulus opening into said chamber radially outside of said first annulus and concentric therewith, said second annulus being connected with the other of said pair of conduits.

8. The drill of claim 7 including a cooling chamber in said nozzle surrounding said combustion chamber having outlet ports adjacent the outlet end of said combustion chamber extending out through the wall of said nozzle; a rotatable core in said body member journaled therein and rigidly attached to the inlet end of said nozzle by an axial conduit surrounding said pair of conduits; a third conduit through said core leading into said axial conduit for introducing coolant to said nozzle; and conduit means connecting said axial conduit with said cooling chamber.

9. The drill of claim 1 wherein said first conduit means comprises a cylindrical chamber which is connected at its open end tothe inlet end of said combustion chamber and is adjacent and coaxial with said combustion chamber of smaller diameter than same, a plurality of conduits tangentially entering said cylindrical chamber, anl annular same, said annulus being connected with the other of said pair of conduits.

10. The drill of claim 9 including a cooling chamber in said nozzle surrounding said combustion chamber having outlet ports adjacent the outlet end of said combustion chamber extending out through the wall of said nozzle; a rotatable core in said body member journaled therein and rigidly attached to the inlet end of said nozzle by an axial conduit surrounding said pair of conduits; a third conduit through said core leading into said axial conduit for introducing coolant to said nozzle; and conduit means connecting said axial conduit with said cooling chamber.

11. The drill of claim 1 wherein the outlet from said combustion chamber is a venturi rocket motor exhaust nozzle having an angle of divergence in the range of: l5 to 35.

12. 'Ihe drill of claim 11 wherein said angle is 25.

13. A thermal drill nozzle comprising a housing; a burner tube of greater length than diameter and of circular transverse section within said housing; means for introducing fluid to the inlet end of said tube longitudinally along the periphery thereof to form a fluid annulus; means for introducing fluid to said inlet end axially of said tube and in a helical pattern around the axis thereof adjacent said fluid annulus; radial drill teeth on the periphery of said housing adapted to cut surrounding material when said nozzle is rotated.

14. The nozzle of claim 13 including an annular cooling chamber intermediate said housing and said tube; ports leading from said chamber through said housing adjacent the outlet end of said nozzle; and a fluid inlet to said chamber adjacent its end opposite said ports.

l5. A process for thermal drilling in an earth .formation which comprises burning a mixture of a combustible fluid fuel and free oxygen-containing gas in an elongated coni-ined combustion zone of circular transverse section and having a greater length than diameter at the shear interface between an annular mass of one of the components of said mixture passed longitudinally along the periphery of said zone and an axial mass of the other component swirling helically adjacent said one component; directing eiuent combustion gas and flame from the outlet of `said zone against an earth formation so as to separate material from said formation in the path of the effluent and form a hole therein; and removing separated material from the hole.

16. The process of claim 15 wherein said fuel is passed along the periphery of the combustion zone.

17. The process of claim l5 wherein oxygen is passed along the periphery of the combustion zone.

18. The process of claim 15 wherein said earth formation comprises rock.

19. The process of claim 15 wherein said fuel comprises a normally liquid hydrocarbon.

20. The drill of claim 9 including an annulus around said combustion chamber between the ends thereof, ports connecting said annulus and said combustion chamber near the outlet of the latter, and conduit means connecting said annulus and said annular conduit.

References Cited in the file of this patent UNITED STATES PATENTS Arnold etal. June 4, 1957 UNITED STATES PATENT OFFICE CERTIFICATE OE CORRECTION Patent No. 2,896,914 July 28, 1959 Martin A. Ryan It is herebr certified that error appears in the-printed specification of the above numbered patent requiring correction and that the said Letters Patent should read as Corrected below.

Column 4, line '72, for "Certaing" read Certain column 5, line 2'7, for "radical" read radial Signed and sealed this 16th day of February 1960.

(SEAL) Attest:

KARL H.,AXLINE ROBERT C. WATSN Commissioner of Patents Attesting Officer 

